Jump to content
SAU Community

Rb25 Dyno Results Summary

M@&k

By M@&k,
in Engines & Forced Induction

 Share

Recommended Posts

M@&k Community Regular

M@&k

Posted
Posted
Hi all,


Have pulled together some info from the RB25 dyno results thread. Only considered some of the more common turbo options (for more data points), and have focussed on those which are internally gated.


Turbos looked at were:

  • HKS GT-RS
  • HKS 2835 Pro S
  • Hypergear SS1PU
  • GT3071
Was originally going to do 3076 as well, but didn't find a whole heap of examples where internal gate was still used.


Have put together two plots. One shows peak power vs boost, and the other shows some dyno curves. Dyno curves are approximate, as I only read off a handful of points from

posted images. Also recorded a bunch of dyno curves in km/hr but cbf trying to convert as not aware of different drive ratios between RB25 variants (e.g. Stag vs Skyline).


Might dig some more in the info later to see if any other trends (e.g. for intercooler types), but nothing was immediately obvious.


Some observations from myself:

  • You're not going to see benefits of the bigger turbos (e.g. 3071) unless you push higher than 16 psi.
  • Those with cams seem to be consistently at the top of the range. i.e. cams are good.
  • Best results were had with Neo engines, but also some strangely poor results with GT-RS.
  • SS1PU looks very good, shame there wasn't more results.
  • Strongest mid range from 2835 Pro S
Some possible conclusions:

  • If you only want to run 16psi, stick with GT-RS (GT28) sized turbos.
  • If you want max mid range (3-5,000rpm) smaller turbine is better.
  • GT3071 really shines > 5,000 rpm, and needs boost.

No groundbreaking insights here. There's obviously a heap of other factors that come into play too, but hopefully is of some interest.

post-83859-0-54689000-1384321535_thumb.jpg

post-83859-0-93135300-1384321548_thumb.jpg

Link to comment
https://www.sau.com.au/forums/topic/434942-rb25-dyno-results-summary/
Share on other sites
M@&k Community Regular

M@&k

Posted
  • Author
Posted (edited)

What housings are used?

Housings weren't always specified. But for HKS and SS1PU turbos I believe they generally only come with one option.

For the GT3071 I expect they were mostly 0.82 AR housings. The exceptions are:

  • the Neo with 301kW @ 17psi which used a 0.63 AR (one of the top 3071 results)
  • the one with the AVO housing (noted on the graph)
  • one with 234kW @ 15psi which has a "modified R33" housing.

Pretty interested to see where the SS2/3 alpha turbos stands. You can get data from our site:

They are on stock cams.

http://www.hypergearturbos.com/atr43alpha.html

Stao, I will look at adding these.

To try and keep things comparable, I was only looking at turbos mounted to the stock manifold, which ruled out your results unfortunately. Might look at a different plot for high mount results...

-----------------------------------------------------------------------------------

EDIT: *** NOTE - THINGS MISSING FROM ORIGINAL POST ***

Results looked at were limited to the following:

  • Stock exhaust manifold
  • 98 pump fuel only

------------------------------------------------------------------------------------

Edited by M@&k

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • sinn3r
      R34 Skyline climate control unit transistor

      By sinn3r · Posted

      I know why it happened and I’m embarrassed to say but I was testing the polarity of one of the led bulb to see which side was positive with a 12v battery and that’s when it decided to fry hoping I didn’t damage anything else
    • MBS206
      R34 Skyline climate control unit transistor

      By MBS206 · Posted

      I came here to note that is a zener diode too base on the info there. Based on that, I'd also be suspicious that replacing it, and it's likely to do the same. A lot of use cases will see it used as either voltage protection, or to create a cheap but relatively stable fixed voltage supply. That would mean it has seen more voltage than it should, and has gone into voltage melt down. If there is something else in the circuit dumping out higher than it should voltages, that needs to be found too. It's quite likely they're trying to use the Zener to limit the voltage that is hitting through to the transistor beside it, so what ever goes to the zener is likely a signal, and they're using the transistor in that circuit to amplify it. Especially as it seems they've also got a capacitor across the zener. Looks like there is meant to be something "noisy" to that zener, and what ever it was, had a melt down. Looking at that picture, it also looks like there's some solder joints that really need redoing, and it might be worth having the whole board properly inspected.  Unfortunately, without being able to stick a multimeter on it, and start tracing it all out, I'm pretty much at a loss now to help. I don't even believe I have a climate control board from an R33 around here to pull apart and see if any of the circuit appears similar to give some ideas.
    • GTSBoy
      R34 GTR Seats / No longer reclining

      By GTSBoy · Posted

      Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • GTSBoy
      Questions on potential new purchase

      By GTSBoy · Posted

      Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • GTSBoy
      Ethanol Content Sensor - Always at 11%?

      By GTSBoy · Posted

      Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
×
×
  • Create New...